Semiconductor devices, such as integrated circuit (IC) packages, typically include a one or more semiconductor devices arranged on a lead frame or carrier. A die attach material affixes a semiconductor die to the lead frame. Bond wires are attached to bond pads on the semiconductor devices and to lead fingers on the carrier. In other instances, one die is mounted on a lower die and affixed thereto in the same manner. The device is then encapsulated to provide protection and form a housing from which the leads extend.
Known die attach materials have been unsatisfactory in many situations. For instance, reliable electrical and thermal binding of the die to the carrier or lower chip (chip on chip) is often problematic.
Adhesives commonly used for die attach films and pastes have limited electrical conductivity due to the limited quantity of electrically conductive particles—typically silver particles are used but the quantity of the silver particles must be limited to limit brittleness. Additionally, such adhesives are prone to separation between the polymer matrix and the electrically conductive filler particles. Known adhesive films also typically include silver particles to provide electrical conductivity, and thus, exhibit similar disadvantages.
For these and other reasons, there is a need for the present invention.